The purpose of this hearing is to receive testimony on efforts to prevent the spread of disease by air travel.

BACKGROUND

Infectious diseases can be spread internationally in a variety of ways, including by travelers, conveyances and goods, and by natural means such as migrating birds. For both economic and health reasons, it is important to be attentive to mitigating the negative impact of travel on public health in an era of rapid and frequent international air travel.

For example, influenza pandemics (worldwide outbreaks of disease) have occurred in 1918, 1957 and 1968 and are associated with excessive mortality and social and economic disruption. As an indication of the potential seriousness of a pandemic, the 1918 influenza pandemic caused over 50 million deaths worldwide (1.5 million in the US) and circled the globe several times within 18 months even before commercial air travel.

More recently, in 2004 and early 2005, many countries in Asia experienced, and continue to experience, unprecedented and widespread outbreaks of avian influenza (“bird flu”) in both birds and humans. Fortunately, the present avian influenza (A) H5N1 strain in Southeast Asia, which causes severe respiratory disease and has high death rates in humans, does not yet have the capability of sustained person-to-person transmission.

Bird-to-human transmission has occurred, and in at least one situation, limited person-to-person transmission has been identified. The world is on high alert for the possibility of another influenza pandemic due to the increasing odds that a new strain of this H5N1 virus more contagious among humans could emerge.

Experts worldwide have recognized that because people would have no immunity to this new virus, avian influenza has the potential to ignite a deadly pandemic.

Given the current threat, the World Health Organization (WHO) has urged all countries to develop or update their influenza pandemic preparedness plans for responding to swiftly-moving contagious diseases, and to address the widespread socioeconomic disruptions that would result from having large numbers of people sick or dying.

With over 1.6 billion passengers traveling worldwide each year, there is increasing concern that potentially deadly pathogens such as Severe Acute Respiratory Syndrome (SARS) can be transmitted around the world in a matter of hours. Moreover, there are also concerns that epidemics might be intentionally caused by terrorists and rapidly transported around the world by airline passengers.

Since the 9/11 attacks in 2001, which propelled the U.S. airline industry into a serious financial condition, the industry has incurred losses of well over $32 billion dollars. These losses are attributed to a variety of factors, including the 9/11 three-day shutdown of the National Airspace System (NAS), the war in Iraq, high fuel prices, and the SARS virus.

Some have estimated that the outbreak of SARS virus in early 2003, which resulted in a sharp decline in passenger traffic to and from Asia and Canada and a corresponding reduction in flights accounted for billions in losses to the airline industry worldwide.

While some travel was curtailed in response to WHO and the Center for Disease Control and Prevention (CDC) travel advisories affecting specific countries, many more people cancelled or postponed air travel to unaffected regions out of general concern and a fear of the unknown.

Probable SARS victims amounted to more than 8,000 cases worldwide between November of 2002 and July 2003. Of these cases, 774 resulted in death. Currently, according to the CDC, there is no known SARS transmission anywhere in the world. At the same time, it is interesting to note that the common flu kills an average of 36,000 people a year in the U.S. alone.

CABIN AIR AND INFECTIOUS DISEASE TRANSMISSION

The principal health concern is not the spread of disease within the aircraft, but the spread of disease around the globe by individuals infected with a disease in one area who then introduce the disease in new geographic areas. In some cases, air travel is so rapid that travelers complete their journeys during the incubation period of the disease and do not even realize they are infected.

The quality of aircraft cabin air is carefully controlled. Exchange with outside air and filtration of recirculated cabin air provide a total change of air 15–20 times per hour. This level of ventilation is much greater than that in buildings and ensures that contaminant levels are kept low. Modern aircraft recirculate up to 50 percent of cabin air. In most aircraft, the recirculated air is passed through HEPA (high-efficiency particulate air) filters, which trap particulate material, bacteria, fungi and most viruses.

Transmission of airborne infectious agents can occur with those in close proximity to the source of infection. Many agree that widespread transmission of influenza may occur on board and this threat can increase on long-haul flights or if the aircraft waits on the ground for an extended period with the ventilation system switched off. To avoid any risk of infecting others or transmitting disease from one country to another, as well as for personal health reasons, WHO recommends that people with contagious diseases should not travel by aircraft.

INTERNATIONAL REGULATIONS

Within the United States, the Secretary of the Department of Health and Human Services has statutory responsibility for preventing the introduction, transmission, and spread of communicable diseases in the United States.

Under its delegated authority, the CDC, through its Division of Global Migration and Quarantine, works to fulfill this responsibility through a variety of activities, including the operation of Quarantine Stations at ports of entry, establishment of standards for medical examination of persons destined for the United States, and administration of interstate and foreign quarantine regulations.

At an international level, the International Health Regulations (IHR), which are administered by WHO, are the only legally binding international instrument covering measures for preventing the transboundary spread of infectious diseases. They provide a single code of procedures and practices, including routine measures at airports and seaports, for preventing the importation of pathogens.

The current regulations, in force since 1969, are now undergoing substantial revision and updating. Intergovernmental negotiating sessions attended by 150 countries were held in November 2004 and February 2005 and a further session is scheduled in May 2005.

The International Health Regulations provide an essential legal framework for the sharing of urgent epidemiological information on transboundary spread of infectious diseases. Their revision will be another important step in strengthening the world’s collective defenses against infectious disease threats.

The revisions acknowledge that measures at border entry points alone are no longer adequate to protect populations against the spread of disease; measures to strengthen disease alert and response will be required. And many specific revisions address problems to strengthen WHO’s outbreak alert and response activities.

Other proposed provisions are designed to ensure the timely and accurate information about public health emergencies of international concern so that recommendations and direct technical assistance, when needed, can be tailored to the event as it unfolds. By following such internationally agreed upon procedures in times of crisis, national authorities should be able to assure their populations that the appropriate measures are being implemented, including procedures for air travel.

THE GLOBAL OUTBREAK ALERT AND RESPONSE NETWORK

The Global Outbreak Alert and Response Network (GOARN) is a technical collaboration of hundreds of existing institutions and networks (administered by WHO) that pool human and technical resources for the rapid identification, confirmation and response to outbreaks of international importance.

The Network provides an operational framework to link the expertise and skill of technical and operational resources from scientific institutions such as the CDC, medical and surveillance initiatives, networks of laboratories, United Nations organizations (e.g. UNICEF, UNHCR, the Red Cross, International Federation of Red Cross and Red Crescent Societies) and others.

GOARN provides technical leadership and coordination in the field and keeps the international community constantly alert to the threat of outbreaks. This organization coordinated the complex international efforts in 2003 to identify the brand new SARS virus and to control the worrisome outbreak of this previously unknown disease, which spread to 29 countries and areas

CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC)

CDC has a “Traveler’s Health Program” which provides advice to individuals planning travel to parts of the world affected by disease, as well as to airlines and other transportation sectors on how to respond to threats of communicable disease.

The Traveler’s Health Program disseminated the SARS guidance and coordinated with the airlines, through the Air Transport Association (ATA), to make sure that U.S. carriers had up-to-date information. CDC is an important contributor to the international GOARN system.

In addition to preventing transmission on the aircraft, the introduction of infectious diseases into the United States can be limited by specific measures both in the U.S. and through partnerships with other countries.

For example, CDC’s quarantine inspectors serve as important guardians of health at borders and ports of entry into the U.S., routinely responding to illnesses in arriving passengers and ensuring that the appropriate medical and/or procedural actions are taken. During the 2003 global outbreak of SARS, CDC's quarantine officials played an important role.

SECURITY AND BIOTERRORISM BY AIR TRAVEL

The Nation’s biodefense strategy, described in Homeland Security Presidential Directive (HSPD)-10: Biodefense for the 21st Century, clearly defines the Department of Homeland Security’s (DHS) role and focuses efforts on non-medical countermeasures. More specifically, DHS Science & Technology (S&T) Biological Countermeasures activities concentrate on providing a scientific assessment of the threat, coordinating surveillance and detection activities, and conducting forensics analysis to support attribution.

Air transportation protection-related activities are in two major areas: (1) protection of airports against biological attacks to include systems designs, concepts of operations and detection systems, and (2) development of advanced detection technologies that have application for protection of individual aircraft, if cost-benefit analyses warrant. In addition, the Commercial Aircraft Protection (CAP) program has initiated a systems study to explore cost-benefit tradeoffs and design of CBRN (chemical, biological, radiological and nuclear) detection systems. Both efforts are described below in more detail.

Airport Protection

A biological attack within an airport has significantly more impact than attacking a single aircraft because many more people can be affected. Therefore, the majority of DHS S&T’s efforts have been focused on this venue. Efforts range from prevention and protection, through detection and warning, to recovering from an attack and restoring operations.

Prevention & Protection

Initial work has focused on an end-to-end look at protecting airports against chemical and biological attacks. Through partnerships with the San Francisco International Airport (SFO) and the Transportation Security Administration (TSA), simple guidelines have been developed for improving airport preparation and protection.

The recommendations are scientifically based to include characterization of airflows, placement and performance of potential detection systems, and evaluation of various mitigation strategies (e.g. altering the airflow in the terminal or evacuating the terminal). Working with airport, regional, state and Federal personnel, pilot testing of a limited biological early-warning system is underway.

Detection and Warning

Early detection of a biological attack is critical to greatly reduce the negative consequences of such event. There are two broad categories of early detection systems: 1) detect-to-treat systems that detect a biological agent in timescales of hours to a day, and 2) detect-to-protect systems that detect in timescales of a few minutes. While the detect-to-protect systems can prevent exposure, detect-to-treat systems identify an agent in time to provide post-exposure treatment, thus reducing morbidity and mortality.

DHS S&T has research and development (R&D) efforts in both areas. Currently, the BioWatch system, which operates in a detect-to-treat mode, is being expanded to increase spatial coverage, especially at critical facilities such as airports. In addition, new technology has been developed and field-tested that can provide a response in one to three hours. Because airports have large numbers of passengers in the terminals on a regular basis, the shorter detection time period will help better identify the exposed population quicker and provide more targeted and rapid treatment.

R&D on detect-to-protect systems, while more technically challenging, currently is underway. Very short detection times (minutes) and continuous coverage operation requires a large number of measurements. These requirements, coupled with a very low false positive rate, are very difficult to accomplish. Current programs addressing this area include, among others, rapid bio-aerosol detector testing in the airport environment and R&D on advanced systems that can detect and identify an agent in minutes with very high sensitivity, specificity, and a very low false positive rate.

Response and Recovery

A biological attack on an airport would ultimately result in significant economic losses due to facility shut down and the interruption of critical services. In partnership with SFO and federal partners to include the Environmental Protection Agency (EPA), the National Institute of Occupational Safety and Health (NIOSH), and the Federal Aviation Administration (FAA), work is underway to generate processes and templates to expedite facility decontamination and restoration of operations.

Current activities include: understanding and reducing the time consuming steps involved in preparing the facility for decontamination; the fumigation process itself; and the subsequent ‘clearance’ sampling that ensure the facility is safe. The guidance resulting from these studies will benefit SFO and other airports.

Aircraft Protection

While the majority of DHS S&T R&D effort has been in airport protection, a systems study has been initiated to explore the needs, issues, technologies, and cost-benefit tradeoffs of possible chemical, biological, and radiological (CBRN) detection systems as part of DHS’s Commercial Aircraft Protection system.

This study is in its early phase and is expected to be completed by the end of the year and guide R&D strategy in this area. It should be pointed out that there are several biological detectors, either available or under development that could be applied to aircraft protection, if the systems study justifies their use.

Several options that currently are available include placing air filters in the aircraft air handling system and removal upon landing for analysis (similar to BioWatch) and deployment of bioaerosol detection systems that nonspecifically detect high concentrations of biological particles rapidly (one minute timeframe).

While the first generation bioaerosol detectors do exist, R&D programs are underway at both DHS and the Defense Advanced Research Project Agency (DARPA) to significantly enhance the performance of these systems while at the same time reducing their cost and size. The Subcommittee will also hear from companies with detection and decontamination products.

Captain Anne Schuchat, MD
Acting Director
National Center for Infectious Diseases
Centers for Disease Control and Prevention
Department of Health and Human Services
Accompanied by
Dr. Ram Koppaka,
Division of
Global Migration and Quarantine
Centers for Disease Control and Prevention

MOSCOW, August 12 (RIA Novosti) - Bird flu is spreading in Russia at a tremendous rate and Siberian farmers have been reduced to hiding chickens from veterinaries in forests, a leading business daily reported Friday.

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